When collecting drum sounds generated by a drum, a microphone for collecting sounds is disposed near the drum or is attached to the drum, for example.
For attaching a microphone to a drum, a microphone holder attached to the rim fixed to the body of the drum (drum shell) has been proposed (for example, refer to Japanese Unexamined Patent Application Publication No. 2009-94851).
The drum includes a drum shell, a drum head, a rim, and tension bolts. The drum shell has a shape of a cylinder having an open top end and an open bottom end, for example. The drum shell has lugs on its side face. The tension bolts each are to be screwed to the respective lugs. The drum heads are stretched on the drum shell with predetermined tension. The method of adjusting the tension applied to the drum head will now be described. The description below takes the drum head stretched on the top of the drum shell as an example.
The circumferential edge of the drum head is pressed downward along the side face of the drum shell by the rim. Thus, the drum head is stretched on the drum shell with predetermined tension. The tension applied to the drum head is adjusted by the vertical movement of the rim along the side face of the drum shell.
That is, the tension applied to the drum head increases as the rim moves downward. When the drum head stretched with increased tension is beaten, the drum generates a drum sound (beat) with a high tone. On the other hand, the tension applied to the drum head decreases as the rim moves upward. When the drum head with a decreased tension is beaten, the drum generates a drum sound with a low tone.
The tension bolts connect the drum shell and the rim. The tension bolts move the rim in the vertical direction (the direction along the side face of the drum shell). The tension bolts each have a threaded portion screwed in the lug of the drum shell. The threaded portion is disposed in the lower end portion of each tension bolt. The upper end portion of the tension bolt is rotatably attached to the rim. The rim moves in the vertical direction along the side face of the drum shell in conjunction with the rotation of the tension bolts. The rotation of the tension bolts is enabled by a tuning key. When the head of a tension bolt is inserted in the socket of the tuning key, and the tuning key is rotated, the tension bolt then rotates. When the tension bolt rotates, the screwed degree of the tension bolt in the lug then varies. As a result, the rim moves in the vertical direction along the side face of the drum shell. That is, when the screwed degree of the tension bolt in the lug is large, the position of the rim in vertical direction is lower than when the screwed degree of the tension bolt is small. As the rim moves downward, the tension applied to the drum head increases.
As described above, the tone of the drum sound generated by the drum is adjusted (tuned) by the adjustment of the position of the rim in the vertical direction relative to the drum shell.